Since the function of the liver is so very complex, it should not come as a surprise that it can play a role in a vast array of diseases. Like so many problems, psoriasis has been treated symptomatically as a skin problem but research is now coming along which links it to more profound causes and suggests that addressing liver damage may be the best way to treat psoriasis.
Psoriasis is a chronic inflammatory disease that affects the skin. Studies have shown that psoriasis is not merely a skin problem; psoriasis is linked with various comorbid conditions, especially obesity and metabolic syndrome [1–5], which are known risk factors for non-alcoholic fatty liver disease (NAFLD).
In the past decade, many studies have drawn attention to comorbid conditions in psoriasis, and preliminary epidemiological data suggest that psoriasis could be associated with the development of NAFLD. Non-alcoholic fatty liver disease includes a spectrum of conditions that range from simple fatty liver, which is relatively benign, to non-alcoholic steatohepatitis (NASH), which can give rise to fibrosis, cirrhosis, and end-stage liver disease . Moderate or severe conditions of psoriasis have a high prevalence of chronic liver disease . It is hypothesised that components of metabolic syndrome as the most likely pathogenic basis may play a role in the manifestation of NAFLD and psoriasis.
Uncontrolled studies have suggested that individuals with psoriasis or psoriatic arthritis may benefit from a diet supplemented with fish oil rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Diet recommendations include consumption of cold water fish (preferably wild fish, not farmed) such as salmon, herring, and mackerel; extra virgin olive oil; legumes; vegetables; fruits; and whole grains; and avoid consumption of alcohol, red meat, and dairy products. The effect of consumption of caffeine (including coffee, black tea, mate, and dark chocolate) remains to be determined.
There is a higher rate of celiac disease among people with psoriasis. Disease severity generally decreases in people with celiac disease and those with anti-gliadin antibodies after the adoption of a gluten-free diet.
Previous studies have suggested links between psoriasis and health conditions such as obesity and metabolic syndrome that can lead to NAFLD, which can cause liver fibrosis and cirrhosis, and end-stage liver disease.
Metabolic syndrome can lead to heart problems and stroke. Its manifestations include high blood pressure, high cholesterol, excess abdominal fat, and other factors.
Many of those with moderate-to-severe psoriasis also have chronic liver disease, supporting the notion of a link between NAFLD and psoriasis.
To find evidence of a link, researchers studied 250 psoriasis patients. Their mean age was 44 and most were overweight, with an average body-mass index of 24.7 kg/m2).
Patients told the researchers how long they had had psoriasis and whether they had hypertension, dyslipidemia — increased cholesterol — and diabetes. Patients’ height, weight, and waistlines also were measured.
Doctors gave all the patients skin evaluations to confirm psoriasis, and a liver ultrasound to detect signs of NAFLD.
Forty-eight percent of the patients were found to have excess abdominal fat, 96% had high cholesterol, 52.8% hyperglycemia, or high blood sugar, 53.6% hypertension, and 44% elevated levels of ALT, an enzyme measure of liver damage.
Almost half the patients, 45.2%, had NAFLD. Those with NAFLD were younger and more obese than those with psoriasis alone. The NAFLD patients, mostly men, also had higher body-mass levels and more metabolic syndrome.
In addition, NAFLD patients had higher fibrosis scores than non-NAFLD patients. None of the NAFLD patients had cirrhosis of the liver, however.
“[NAFLD] is highly prevalent among our cohort of patients with psoriasis, occurring in 45.2% of patients,” the researchers wrote. “Comorbidity of NAFLD is highly associated with psoriasis, which emphasizes that both diseases may develop simultaneously. Healthcare providers should be mindful of this association since early evaluation and diagnosis of NAFLD in patients with psoriasis may play a vital role in alleviating the progression of liver disease.”